This invention relates to lancet devices particularly for medical use to extract a patient's blood sample, and more particularly relates to mechanism for automatic operation of a lancet needle to initially penetrate and thereafter immediately retract the needle from the skin in a blood sampling procedure.
In order to reduce trauma to the patient during blood sampling procedures, automated finger lancet devices have been developed which eliminate the patient's view of both the skin puncture and the lancet needle or blade itself. As described for example in U.S. Pat. Nos. 4,539,988; 4,892,097; and 5,212,879, the lancet blade or needle can be housed within a small device which provides a spring-driven mechanism for thrusting and retracting the blade or needle. While such devices obstruct the patient's view, considerable patient discomfort has been experienced with lateral or rotary blade motion. Accordingly, as described for example in U.S. Pat. Nos. 4,924,879; 5,196,025; and 5,318,583, lancet devices have been developed which provide improved patient comfort by moving the lancet needle in rapid continuous thrusting and retracting motion along a linear path to eliminate lateral movement.
Lancet devices in accordance with the present invention provide improvement in construction, operation, user comfort, and disposibility as well as handling safety.